RU18312U1 - DEVICE FOR MEASURING THE VALUE AND DIRECT CURRENT DIRECTIONS IN METAL PIPELINES - Google Patents

Abstract

A device for measuring the magnitude and direction of direct current in metal pipelines, containing a control and measuring point, a measuring unit, characterized in that the measuring unit includes a voltage drop measuring unit, a comparison unit and a compensation current setting unit, an adjustable DC direct current source, a measured current recorder moreover, the voltage drop measuring unit is connected to the terminals of the control and measuring point, and the output to the comparison and setting unit of the compensation current, and the comparison unit is set The compensation current is connected to an adjustable reversible direct current source with one output, and the other to a measured current recorder, and an adjustable reversible direct current source is connected to the terminals of the test point.

Description

2000128775

DEVICE FOR MEASURING THE VALUE AND DIRECT CURRENT DIRECTION IN METAL PIPELINES

The solution relates to measuring equipment and can be used to measure direct currents flowing in metal pipelines above and below ground due to the cathodic protection of pipelines or the harmful effects on pipelines of objects that are sources of stray currents (electrified direct current railways, tram transport, and metro , electrotechnological installations).

A device for measuring currents flowing through a pipeline is known. Nowadays, direct current measurement in pipelines is carried out by the contact method (Operation manual for anticorrosion protection of underground gas pipelines, VNIIGAZ, -M., 1986).

As a prototype, a device for measuring current in a pipeline was selected (Messtechnik beim kathodischen Korrosionsschutz / Walter von Baeckmann ... 3., verb. Aufl. Ehningen bei Boblingen: expert-Veri. 1992). To measure the direct current flowing through the pipeline, the equipment of special control and measuring points is necessary. When connecting an external current source and a millivoltmeter to the terminals of the control and measuring point, a number of measurements are made when current is applied. Based on the results obtained, the linear electrical resistance of the pipeline section on which the measurements are made is calculated by the expression:

where R is the resistance of the controlled section of the pipeline. Ohm;

SC 7 (30IR 17/00

R.

AU - change in voltage drop in the controlled area, caused by this change in current, V.

Then, in this section of the pipeline, it is possible to measure the current flowing through the pipeline by the magnitude of the detected voltage drop, multiplying it by the already known electrical resistance of the controlled section of the pipeline.

However, this device has several disadvantages. The operation of preliminary measurement of the resistance of the pipeline section is required. When carrying out regular measurements on a large number of control and measuring points for measuring current, it is necessary to maintain a statement of the parameters of these points or marking these parameters in the measurement sites themselves. The source device does not provide for automatic recording of the measured current value. Subsequent measurements do not take into account the possible change in the resistance of the pipeline section (with a significant change in the temperature of the transported product and the environment), possible malfunctions of the control and measuring point, which does not allow to increase the accuracy of measurements.

The problem solved by the utility model is the improvement of a device for measuring the magnitude and direction of direct current in metal pipelines.

The technical result from the use of the utility model is to increase the accuracy of measuring direct current in the pipeline and the convenience of measurements.

The specified technical result is achieved by the fact that in the device for measuring the magnitude and direction of direct current in metal pipelines, containing a control and measuring point, a measuring unit, into which a voltage drop measuring unit, a comparison unit and a compensation current setting unit, an adjustable reversible direct current source are inserted, the measured current recorder, and the voltage drop measuring unit is connected to the terminals of the test point, and the output to the comparison and reference current compensation unit tion, and a comparison unit and setting the compensation current is connected to an adjustable reversing

a direct current source with one output, and the other with a measured current recorder, adjustable reversible direct current source is connected to the terminals of the control and measuring point.

Improving the accuracy and convenience of measurements is due to the possibility of an automatic measurement mode to take into account external factors affecting the pipeline, since the device directly measures the compensation current, which is equal in magnitude and opposite in direction to the current in the pipeline. A possible change in the electrical resistivity of the pipeline section will not affect the accuracy of the direct current measurement.

Figure 1 shows a structural diagram of a device for measuring the direction and magnitude of direct current in metal pipelines.

The device comprises a control and measuring point 1, a measuring unit 2, a unit for measuring the voltage drop 3, a unit for comparing and setting the compensation current 4, an adjustable reversible direct current source 5, a recorder for the measured current 6, and the unit for measuring the voltage drop 3 is connected to terminals 8, 9 control point 1, and the output to the unit for comparing and setting the compensation current 4, and the unit for comparing and setting the compensation current 4 is connected to an adjustable reversible DC source 5 with one output and the other to the regis to the tracer of the measured current 6, an adjustable reversible DC source 5 is connected to the terminals 7, 10 of the control and measuring point 1.

A device for measuring the magnitude and direction of direct current in metal pipelines works as follows.

The voltage drop measuring unit 3, connected to the middle terminals 8, 9 of the control and measuring point 1, receives a potential difference signal

pipeline, due to a voltage drop in a controlled section of the pipeline under the action of direct current flowing through it. The signal at the output of the voltage drop measuring unit 3 is the driving signal for the comparison and setting unit of the compensation current 4. The comparison and setting unit of the compensation current 4, in turn, generates a reference signal for an adjustable reversible direct current source 5. In this case, the purpose of regulation is to provide such directions and values of direct current compensation supplied to the terminals 7, 10 of the control and measuring point 1, in which the potential difference in the monitored section of the pipeline arriving at the block from 3 Eren voltage drop will Governing 0. This compensation current generated by the device will ravnm in magnitude and opposite in direction to the current flowing through the pipeline. When the measurement mode is established and the necessary requirements are met for the accuracy and speed of all nodes of the device, the reference signal generated by the comparison and reference unit for compensation current 4 will contain information about the magnitude and direction of the compensation current and, accordingly, the current in the pipeline. Indication and registration of this signal is performed by the measured current recorder 6.

The proposed device for measuring the magnitude and direction of direct current in metal pipelines increases the accuracy of measuring direct current due to the ability to automatically measure and take into account external factors affecting the pipeline, and the convenience of measurements.

Claims (1)

A device for measuring the magnitude and direction of direct current in metal pipelines, containing a control and measuring point, a measuring unit, characterized in that the measuring unit includes a voltage drop measuring unit, a comparison and compensation current setting unit, an adjustable reversible direct current source, a measured current recorder moreover, the voltage drop measuring unit is connected to the terminals of the control and measuring point, and the output is connected to the comparison and setting unit of the compensation current, and the comparison unit is set The compensation current is connected to an adjustable reversible direct current source with one output and the other to a measured current recorder, and an adjustable reversible direct current source is connected to the terminals of the control and measuring station.